(1) Field of the Invention
The present invention relates to a process for the parallel identification and authentication of objects and to a device for identifying and/or authenticating objects.
The automatic identification of objects by optical methods is known in the prior art. Everyone is familiar, for example, with bar codes which are applied to products and/or packaging and which allow the automatic identification of products for determining, for example, their price.
(2) Description of Related Art
One known example of a bar code is the EAN 8 code which is defined in International Standard ISO/IEC 15420. This is a code with a string of 8 digits in the form of bars and gaps of varying widths. Usually the bars are printed in black printing ink on a white substrate, such as for example the packaging of the object to be marked, or on the object itself. The code is machine-read by scanning it with a suitable light source and capturing the reflected light with a detector. Since the dark bars reflect less light than the bright gaps, the reflected light beam displays corresponding differences in brightness which are identified by the detector and converted into electronic signals. The electronic signals are analyzed by microprocessors. Usually the decoded string of digits is emitted via an output channel.
In addition to the abovementioned EAN 8 code, numerous other bar codes exist which encode not only digits but also letters, special characters and control characters. In addition, some codes contain error-detecting and error-correcting characters which allow errors in signal transmission to be detected and even in some cases to be corrected.
One further development of bar codes consists of 2D codes, in which the information is optically encoded not only one-dimensionally but also in two dimensions. One subgroup of 2D codes consists of so-called matrix codes, one known example of which is the data matrix code defined in International Standard ISO/IEC 16022. The advantage of matrix codes is their higher information density. Depending on the size of the data matrix code, up to 2334 ASCII characters (seven bits), 1558 extended ASCII characters (eight bits) or 3116 digits can be encoded. Whereas one-dimensional bar codes are usually read by scanning them with a focussed beam of light, two-dimensional matrix codes are read using camera systems, which is why matrix codes have so-called “finder patterns” for guiding the reading device.
In the following, bar codes, 2D codes and matrix codes will be jointly referred to as optical codes. Optical codes can be produced simply and in an extremely inexpensive manner (by printing) and can be scanned quickly and robustly. They are ideally suitable for the identification of objects. In particular, optical codes are suitable for tracking and tracing objects. For this purpose the object is given a number to allow it to be identified at each stage of the logistic chain and its movement to be traced from one stage of the logistic chain to another.
Optical codes are, however, simple to copy, reproduce and fake and cannot therefore be used for the authentication of objects.
Objects do, however, exist which are required to be individually re-identified and authenticated at a later date. One simple example of such objects consists of ID cards. ID cards must be individually unique. With the increase in automation the uniqueness of each ID card must be machine-readable.
RFID chips can be used for this purpose. They contain a secret key which cannot be read from the outside. When communicating with an RFID chip, messages from the chip are encrypted by this secret key. These messages can be decrypted by a corresponding public key. Since the secret key is not, however, accessible it is very difficult to create a duplicate or dummy (a fake). By attaching RFID chips to objects it is therefore fundamentally possible to identify and authenticate such objects. Many objects do however exist which, for technical and/or economic reasons, cannot be fitted with an RFID chip. RFID chips are, for example, liable to crack and susceptible to damage from electromagnetic interference fields. RFID chips are far more expensive than printed optical codes. In addition, there have recently been increasing reports of faked or counterfeited RFID chips.
WO 2005088533(A1) describes a process which does not require any additional data carrier (optical code, RIFD chip) for identifying and authenticating an object and which enables objects to be clearly allocated by means of their surface structure. For this purpose, a laser beam is focussed on the surface of the object, moved over its surface (scanning) and the beams scattered to differing degrees and at various angles at different points on the surface of the object are detected by photodetectors. The scattered radiation detected by this process is typical of many different materials and is very difficult to fake since it is caused by incidental phenomena during the manufacturing process of the materials. Paper-like objects, for example, have a fibrous structure due to their manufacturing process which is unique for each object produced. The scattering data of the individual objects is stored in a database in order to be able to authenticate the object at a later date. To this end the object is scanned once again and the scattering data compared with the stored reference data.
The disadvantage of the above process is that a comprehensive database has to be created for the scattering data of all the scanned objects. Not only does this database have to have a high storage capacity for storing the high quantities of scattering data of a large number of objects but quick access to the data in the database must be possible since authentication requires comparing the scanned scattering data with all of the reference data in the database, in order to find the correct data set. Due to positioning inaccuracies during scanning, slight changes in the scattering pattern of the object over time (due to soiling, wear, etc.) and technical differences between the various scanning devices, the scanned scattering data of an object are never absolutely identical but display variations. It is therefore necessary to make a comparison with all of the reference data in order to find the most identical data set. In addition, the positioning of the object beneath the scanning device must be sufficiently accurate to provide sufficiently precise identity during the matching process. In simple terms this means ensuring that the region used for authentication is always the same. This means that the object must be positioned in relation to the scanning device. The positioning accuracy must be considerably higher than in the case of optical codes, as quickly becomes clear on comparing the dimensions of the bars and gaps of a bar code with the dimensions of the scattering centres of a paper-like object. Higher positioning accuracy does however actually mean a longer time for scanning an object (the time for preparing for the measurement+the measuring time). Whereas optical codes only have to be placed in the optical field of view of a scanner, in the case of WO 2005088533(A1), the scattering pattern of an object can only be determined if it is precisely aligned and fixed in relation to the scanning unit.
Due to the above disadvantages, the process of WO 2005088533(A1) is only suitable to a very limited extent for identifying and tracing objects. Also, identification solutions based on the scanning of optical codes are well-established. An IT infrastructure does therefore already exist for optical codes which, for the abovementioned reasons, cannot be used for the process of WO 2005088533(A1). Before the process of WO 2005088533(A1) could be used, a new IT infrastructure would be required or at least the expansion of the existing IT infrastructure, which would make it difficult to introduce the process of WO 2005088533(A1) onto the market (a high market entry barrier). The straight migration from established technology (identification based on the scanning of optical codes) to a new technology (identification and authentication by recording the scattering pattern) is not possible.
It can therefore be affirmed that processes and devices for identifying and authenticating objects are known from the prior art. Processes and devices for identifying objects by means of optical codes are, however, due to the ease with which the features used for identification can be faked, not suitable for the authentication of objects. Conversely, although the authentication process of WO 2005088533(A1) is ideal for authentication, it is not suitable for tracking and tracing objects due to the high quantities of data involved and the correspondingly high demands on the IT backend system (the database/network), the high demands on positioning accuracy and the corresponding long duration of the scanning process.
Thus, given the known prior art, the problem arose of providing a process which allows objects to be identified and authenticated while as far as possible being able to use the existing IT infrastructure for existing identification solutions. The process should be inexpensive and have a low market entry barrier. It should be robust and simple to handle by users. If possible, the process should not require any reaccustomation on the part of users but its use should be similar to that of existing processes.